Process of manufacturing corrugated furnace flues or tubes.



No. 743,193. 'PATENTED Nov, 3, 190a.

w. RAINPORTH. PROCESS OF MANUFACTURING CORRUGATED FURNACE FLUES 0R TUBES.

APPLICATION FILED AUG. 8. 1902..

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FIG. I.-

No. 743,193. PATENTBD NOV. a, 1903.

W. ;RAINPORTH. v PROCESS or MANUFACTURING CORRUGATED FURNACE FLUES 0R TUBES.

APPLICATION FILED AUG. 8' 1902.

K0 MODEL.

2 SHEETS-SHEET 2.

UNITED STATES Patented November 3, 1903.

' WILLIAM RAINFORTH, OF UPPER ARMLEY, LEEDS, ENGLAND.

PROCESS OF MANUFACTURING CORRUGATED FURNACE FLUES 0R TUBES.

.SPECIFIGATION forming part of Letters Patent No. 743,193, dated November 3, 1903.

Original application filed April 23, 1902, Serial No. 104.399. Divided and this application filed August 8, 1902. Serial To all whom, it may concern.-

Be it known that I, WILLIAM RAINEORTH, a subject of the King of Great Britain and Ireland, residing at Upper Armley, Leeds, in the county of York, England, have invented a new and useful Improved Process for the Manufacture of Corrugated Furnace Flues or Tubes, of which the following is a specification.

This invention relates to the manufacture of steam-boiler furnace fines or tubes of the class whose walls are of a longitudinal sectional form, resembling arch-like outward projections or inward projections connected by intervening portions inwardly curved or otherwise formed. Many varieties of such furnace flues or tubes have been constructed and proposed to be constructed-in some cases by rolling and in some cases by swaging, by means of a steam-hammer or hydraulic or other press, in a manner to impart what has been known as corrugations to the metal which has been previously or subsequently brought to the general form of a furnace flue or tube; but the methods and means theretofore usually employed have not been such as to result in the production com mercially of furnace lines or tubes of the kinds referred to having bends or curves as pronounced as those I contemplate, there be ing in practice-as, for example, in a rollingmill-a tendency to detrimental local thinning of the wall of the furnace flue or tube under treatment. Thus, for instance, as is well known, it is practically impossible to produce a literally sharp sectionin afurnace fine or tube by rollingjthe sharpness of any section being governed by thethi cliness of the metal used.

Now, according to this invention, in order to produce a furnace flue or tube with pronounced bends or curves in its wall the desired bends or curves are partially formed by a rolling process, and afterward the furnace flue or tube is subjected to endwise pressure in such a manner that there is an appreciable shortening of the furnace flue and the forma tion of the desired pronounced bends or curves is completed without undue stress or thinning of the metal. The preliminary corrugating process is effected by rolling, as well uuder- (No model.)

stood, and the completion of the pronounced bends or curves by pressure endwise of the furnace flue or tube is effected by the use of any suitable pressing apparatus in conjunction with any means adapted to prevent deformation of the flue, and suitable guiding and confining means to limit the end pressure effects to produce the sharpening of the bends or curves of the circumferential ridges, as desired. In order that the wall ofthe flue or tube may be uniformly bent or curved, the intermediate portions of the flue or tube are supported while it is being subjected to end- Wise pressure in such manner as to rigidly resist or limit inward movements of any part of each intermediate portion without tending to force outwardly any part of the corrugations being subject to end pressure.

The accompanying drawings show as an example an elfect that it may be desired to produce by myimproved method of operation.

Figure 1 is a vertical section through a corrugated flue such as may be produced by the known methods of rolling a plain cylindrical line or tube. Fig. 2 is a vertical section through such flue after it has been subjected to an end pressure longitudinal to the axis so as to appreciably shorten the flue or tube, forming the desired pronounced or sharpened bends in the circumferential corrugations. Fig. 3 is a longitudinal section of the flue, showing suitable internal and external means for rigid support and control as to the exact form and dimensions of the resulting sharpened circumferential ridges under endwise pressure.

Usually the partiallycorrugated flue or tube is subjected to endwise pressure while in a heated condition, and in such cases if a rigid support were not employed there would be even greater tendency for the corrugations to be bent unevenly; but by simultaneously rigidly supporting the intermediate portions of the fine or tube and subjecting it to endwise pressure in accordance with this invention fines or tubes with pronounced bends or curves of uniform shape can be produced.

It is obvious that many varieties of modifications of the contour of the circumferential outwardly-projecting ridges may be formed by this system of end pressure longitudinal Ice to the axis upon the flue-via, the lower walls of the circumferential outwardly-projecting ridges close to the body of the flue may be pressed together by the longitudinal pressure closer than the upper curved summit of the ridges, thus forming bulb-like circumferential ridges with reenter-ing sides, such as would be impossible of production by rolling or any known system of pressure exerted perpendicularly to the axis of the flue.

Among the many forms vof furnace dues or tubes for the production of which my improved process may be employed I may mention such as are constructed according to the invention of Ernest Gearing, which forms the subject-matter of an application for Letters Patent deposited by him the same day as my original application, of which this application is a divided part.

For carrying this process into effect I have devised special apparatus; but such apparatus is not herein disclosed or claimed, but forms the subject-matter of my original application, deposited on the 23d day of April, 1902, under Serial No. 104,399, of which this application is a divided part. As suit-able means for carrying out the process as above described a vertically-divided cylindrical casing A, Fig. 3, may be used, into which when divided and apart a flue or tube may be lowered or placed after it has been treated by rolling to produce its first condition of shallow corrugations, as shown in Fig. 1.

While the flue is so suspended, a mandrel B,

which is preferably expandible and collapsible, is inserted in a collapsed condition into the flue after the mandrel has been clothed or surrounded by segmental rings 0 (of suitable external periphery to gage the required size of the finished hollows within the deepened circumferential bends) and by plain segmental rings 0 at each end within that portion of the tube or flue which is intended to be finished plain and without corrugations. The mandrel B is supported by and thrust out from a fixed standard-bracket or bedplate D by any suitable means and if expansible has conveniently an internal core E, capable of longitudinal movement to the mandrel, say, byva screw-thread and handwheel nut F, and carrying longitudinal segmental slippers G by parallel toggle-levers H for the support of the aforesaid external segmental rings 0. When 'the said mandrel is expanded in place within the flue or tube, the latter is now supported on the internal mandrel and segments and the suspending-chains 'or other external support can be removed.

will have been produced in the shallow corrugated flue or tube. The outer segmentsK being in place, the divided casingA is closed and locked, firmly embracing radially all the external segment-rings K, but permitting them freedom to move laterally or longitudinally to the flue, and the final compression laterally or endwise to the flue of all the said external and internal segmentrings, and thus of the flue, is now produced by a ram L of a suitable hydraulic press, connected by ties M to the aforesaid fixed part of the bedplate D, and the described process is completed with accuracy and uniformity of result.

In conclusion, while reserving to myself the right to varythe forms or proportions of the pronounced bends in the corrugated outwardly-projecting ridges as may be desired, what I claim, and desire to secure by Letters Patent, is

A process for producing a furnace tube or flue with pronounced circumferential ridges or curves in its wall consisting of, first, forming a plain cylindrical flue; secondly, forming therein uniform circumferential hollow ridges and projections; thirdly, rigidly supporting said flue from within; fourthly, sub- 9 jecting said flue to endwise pressure while being rigidly supported from within to sharpen the curves of said circumferential ridges with accuracy as to spacing and form.

In witness whereof I have hereunto set my hand in presence of two witnesses.

WILLIAM RAINFORTH.

Witnesses:

WILLIAM JOHNSTON, HARRY SIDNEY HEPWORTH. 

